Barca have been trying to re-sign the Brazil international throughout the entire summer but have yet to come to an agreement with PSG.
Both clubs value the Brazilian forward at €200m (£181m) and the Spanish champions have offered a cash-plus-player deal involving Jean-Clair Todibo and Ivan Rakitic, plus Dembele on a season-long loan.
However, all three players have rejected the move and that has cast doubt over a possible return for Neymar at the Nou Camp.
Guillem Balague hinted on Twitter that Dembele is particularly crucial in the negotiations ahead of Monday’s transfer deadline day.
But the former Borussia Dortmund star has yet to be convinced and so Neymar’s move will probably not happen, much to his family’s disappointment.
Balague echoed a statement by Spanish sports journalist Helena Condis Edo who claims the Brazilian is “very screwed”.
He tweeted: “The Neymars are “very upset”.
“It is “almost impossible” which is the same message the club is giving too.
“They are not able to convince Dembele.
“Time is practically up on this one now.”
PSG sporting director Leonardo said on Friday that no agreement has been reached for Neymar.
The former Brazil international also pointed out that there will be no breakthrough until the French champions’ demands are met.
Leonardo said: “Our position on a potential departure of Neymar is clear, everyone knows what we want.
“We got a first written offer on 27 August and we refused it, the conditions didn’t suit us.
“There are three days until the end of the transfer window, and for the moment, there is no agreement.
“We’re talking a lot, with Neymar in particular. He’s an extraordinary player, I didn’t know him personally before I came back to Paris.
“He has gone through a lot of things, he’s a football star today, and I like him a lot. We have a good relationship with him.”